Pds Sikka Bajda Final 95mw May 09aaa
Transcript of Pds Sikka Bajda Final 95mw May 09aaa
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A PROPOSAL FOR AN OFFSHORE
WINDFARM AT IS-SIKKA L-BAJDA
PROJECT DESCRIPTION STATEMENT
MINISTRY FOR RESOURCES AND RURAL AFFAIRS
April 2009
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The purpose of this Project Description Document is to enable MEPA to take a
screening decision regarding whether an Environmental Impact Assessment is
required and, if in the affirmative, whether this should be a full EIA (EIS) or a limited
EIA (EPS), and to prepare the terms of reference for such an EIA, in consultation
with the Government entities, Non-Governmental Organisations and the public.
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CONTENTS
CHAPTER1. INTRODUCTION....6
1.1 Background to the Project....6
1.2 Maltas Renewable Energy Targets. ..8
1.3 Assessments of the Local Potential for Offshore Wind Energy..8
1.4 Project Proponent....11
CHAPTER2. OBJECTIVES OF THE PROPOSED DEVELOPMENT......12
2.1 Benefits of the Development..13
2.2 Proposed Timing..13
CHAPTER3. PHYSICAL CHARACTERISTICS OF THE SITE....15
3.1 Site Selection Criteria for Offshore Wind Farm.......15
3.2 Site Location and Description....16
3.3 Physical Characteristics......16
3.4 Environmental Aspects.......16
3.5 Site Usage.203.6 Wind Resources at Site...21
CHAPTER4. DESCRIPTION OF THE PROJECT......23
4.1 Detailed Components of The Proposed Development......23
4.2 Wind Farm Design...25
4.3 Pre-Construction Engineering and Environmental Studies..........41
4.4 Component Delivery and Wind Farm Construction....514.5 Operation and Maintenance of the Wind Farm...57
4.6 Decommissioning.....59
4.7 Health and Safety Measures......60
4.8 Raw Materials and Waste...62
4.9 Employment..62
4.10 Projects Costs and Economic Feasibility63
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CHAPTER5. SITE SELECTION FOR OFFSHORE WIND FARM IN MALTA......66
5.1 Status of Offshore Wind Turbine Technology.........66
5.2 Candidate Shallow Water Sites for Offshore Wind Turbine Technology....68
5.3 Selection of the Best Candidate Site for Offshore Wind Farm.....70
CHAPTER6. ENVIRONMENTAL IMPACTS AND PROPOSED MITIGATION MEASURES .....82
6.1 Visual Impact........82
6.2 Noise Generation during Turbine Operation.......83
6.3 Shadow Flicker........83
6.4 Impacts on Marine Life....846.5 Impacts on Birds...86
CHAPTER7. IMPACTS ON OTHER ACTIVITIES ...........................................................88
7.1 Bunkering and Other Marine Traffic......88
7.2 Fishing Industry....88
7.3 Tourism Industry...89
7.4 Marine Archaeology.....89
7.5 Other Activities..89
CHAPTER8. PRELIMINARY CONCLUSIONS................................................................90
REFERENCES...91
APPENDICES.......93
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Abbreviations
SAC Special Area of Conservation
SPA Special Protected Area
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CHAPTER1. INTRODUCTION
1.1 Background to the Project
1.1.1 Project Summary
This document presents a Project Description Statement (PDS) for the development
of a close to shore offshore wind farm at Is-Sikka l-Bajda which is located on the
North-East coast of Malta, about 1.5 km off the coast of Rdum tal-Madonna, limits of
Mellieha. This PDS sets out the basis to enable MEPA to take a screening decision
regarding whether an Environmental Impact Assessment is required and, if in the
affirmative, whether this should be a full EIA (EIS) or a limited EIA (EPS), and to
prepare the terms of reference for such an EIA, in consultation with the Government
entities, Non-Governmental Organisations and the public. The wind farm will have a
capacity of up to 95 MW1 (Megawatts) and will be known as the Sikka l-Bajda Wind
Farm. The allocated site will be studied in detail to investigate its potential for wind
farm development in further depth and to assess the associated environmental
impacts. Eventually the site will be made available to a selected developer following a
selection process. The developer will construct and operate the wind farm for a period
of around 20-25 years after which the wind farm will be de-commissioned and the
wind turbines and other related systems removed.
The proposed Sikka l-Bajda wind farm would be located 3 to 5 km from the tourist
accommodation area of St. Pauls Bay, Bugibba and Qawra and 5 km away from
Ghadira beach. The closest residential area is Qawra (Ta Fra Ben area), about 3
km from the nearest turbine. The project covers a sea area of around 11 square
kilometres with water depths varying between 10 to 35 m.
The Sikka l-Bajda wind farm will consist of up to 19 five-Megawatt wind turbines with
a maximum generating capacity of 95 MW. The wind turbines will be connected to
the national electricity grid through an onshore substation. The operation of the wind
farm will be closely monitored through a sophisticated supervisory control and data
acquisition (SCADA) system. A network of undersea electrical power cables will
transmit the power from the individual turbines. The cables will either be laid on the
sea-bed or buried. The cables will export the electricity from the wind farm to the
onshore substation. Some trenching will be required on land to bury the cables in the
path between the coast and the onshore substation.
1
The final wind farm size will be depend on the outcome of detailed technical and environmental studies. Thetechnical studies include a grid integration study which will be performed in close cooperation with Enemalta.
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The proposal also includes the installation of wind monitoring equipment, offshore on
site or at a nearby onshore location to undertake the necessary wind studies prior to
developing the project. Environmental, geophysical and geotechnical surveys also
need to be carried out.
The Sikka l-Bajda wind farm would provide a significant source of clean, renewable
electricity that would make a major contribution towards meeting the Maltas
renewable energy target of 10% by 2020. Once completed the Sikka l-Bajda offshore
wind farm will be capable of generating enough energy for around 45,000
households2. The wind farm will supply the north of Malta and Gozo with at least 180
gigawatt-hours of clean electricity annually. This is equivalent to around 7.5% of the
present (2008) global electricity consumption in Malta and 5.5% of the forecasted
consumption for 2020. It is estimated that Sikka l-Bajda offshore wind farm could
offset approximately 185,000 tonnes of carbon dioxide emissions annually per year
compared with electricity that could otherwise be generated from an oil-fired power
station3and save circa 390,000 barrels of heavy fuel oil imports every year.
1.1.2 The Environmental Impact Assessment (EIA) Process
The proposed Project is subject to the EIA Regulations of 2007 (L.N. 114), which form
Article 60 of the Development Planning Act. As the Project is listed under Category II
of Schedule 1A of the Regulations, it requires a limited EIA and the preparation of an
Environmental Planning Statement (EPS). More specifically this proposed
development is listed under Schedule IA as:
Section 7.5.2 Renewable Energy Production Category II Projects:
Installations for the harnessing of wind power for energy production (wind farms) in
excess of 5 turbines or in excess of a total output of 5 MW.
Prior to the limited EIA being carried out, a PDS is required to accompany the
application for development permission. Appendix A outlines the information that a
PDS for this specific project should contain.
2Based on a household daily consumption of 13 Kilowatt-hours per day
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1.2 Maltas Renewable Energy Targets
EU Directive 2001/77/EC on the promotion of electricity generated from renewable energy
sources (RES) in the internal electricity market sets an overall EU target of 21% for electricity
produced from renewable energy sources by 2010. The Treaty of Accession sets Maltas
reference value for electricity generated from renewable energy sources at 5% of the
electricity generated in 2010. This figure was established on the basis of high level estimates
by the EU Commission. The 5% value was made on the basis of an estimated gross national
electricity consumption of 2 TWh in 2010 and subdivided as follows:
(i) 1.93% of total electricity demand for 2010 generated from wind (15 MW for an
annual electricity production of around 39 GWh/annum in 2010);
(ii) 3% of 2010 electricity demand generated from biomass (equivalent to around 60
GWh/annum in 2010).
In March 2007, the European Council agreed on a new energy package for Europe. The
main objective of this energy package is an EU commitment to achieve, at least a 20%
reduction of greenhouse gases by 2020 compared to 1990. A target of 10% renewable
energy of the final energy consumption has been set for Malta by the EU Commission.
1.3 Assessments of the Local Potential for Offshore Wind Energy
1.3.1 Status of Past Assessments
Various detailed assessments on the potential of renewable energy exploitation in
Malta have been carried out. In 2005, Malta commissioned Mott MacDonald Ltd to
carry out a study to assess the potential of electricity generation from renewable
sources until 2010 and post 2010. The potential for offshore wind farm development
was also assessed (Mott MacDonald, 2005).
In 2005 the MRA carried out various studies on the offshore wind energy potential in
order to identify sites at a depth of below 20 m with potential to host large-scale
offshore wind farms. The sites that were investigated and examined in detail
included: Is-Sikka l-Bajda, Ras il-Griebe, Il-Ponta tal-Qawra, Gallis Rocks, Marku
Shoal, Madliena Shoals, St. Georges Shoals, Sikka l-Munxar, Bengajsa Patch and
amrija Bank. In addition Government also directed the Authority to study a
relatively deepwater water site located north east of Sikka l-Bajda. Extensive
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consultation with Government departments, entities and authorities was carried out
and a review of the impacts identified and reported to Government.4
In 2006, given the progress of deepwater technology and the perceived negative
impact of near-shore technology, the Malta Resources Authority published a Call forExpressions of Interest (EOI) for offshore wind farm development. The purpose of
the call for EOI was to gauge the interest of developers in a deepwater project and to
identify promising technologies that can be exploited within Maltese territorial waters.
This Call was again preceded by an extensive stakeholder consultation exercise with
the contribution of Government agencies, authorities and key stakeholders to
determine the potential sites and associated impacts for offshore wind farms.5
An assessment of the responses received in the Call for EOI indicated that the main
difficulty lies in the substructure design and Government is therefore closely following
developments in two substructure technologies: floating technologies and
tripod/quattropod jacket technologies.6
1.3.2 Committee on Wind Energy
Last year the Minister for Resources and Rural Affairs also set up a Wind Energy
Committee consisting of independent experts to re-assess Government agencies
submissions in Malta Resources Authoritys consultative exercise with respect to Is-
Sikka l-Bajda, which is the shallow water site offering the greatest potential. It has
been assisted by German experts from the Federal Ministry for Environment, Nature
Conservation and Nuclear Safety. The Wind Energy Committee emphasised on the
need to realise an offshore wind farm project in the short-term, as part of a renewable
4 A networking approach was adopted with consultations with key Government agencies including: MaltaMaritime Authority Malta Environment and Planning Authority, Malta Tourism Authority, FisheriesConservation and Control Division, Enemalta Corporation, Malta Communications Authority,Department of Civil Aviation, Malta International Airport, Malta Air Traffic Services Ltd., Oil ExplorationDepartment, Armed Forces of Malta, Malta Enterprise and Kunsill Malti Gall-Isport.
5Territorial waters were consequently categorised as follows:
(i) no go areas which were areas indicated by respective stakeholders where no offshorewindfarm development should be authorised due to the unacceptable impacts or risksassociated with such development.
(ii) sensitive areas which were areas indicated by the stakeholders as being potentially restrictedto windfarm development in view of serious conflict(s) with important key economic activities ordue to possible adverse negative impacts arising from any such development.
(iii) other areas which prima faciewere considered as areas where offshore windfarm developmentwould be acceptable and subject to normal environmental impact assessment procedures andother studies in accordance with the Environmental Impact Assessment Regulations.
6Both these technologies are in the demonstration phase. The first is being demonstrated through a scale
prototype at a distance of 10.6 nautical miles from the coast in Southern Italy. The second is beingdemonstrated through two wind turbine generators of 5 MW each in 45 m deepwater near the BeatriceAlpha oil production platform in the Moray Firth offshore North East Scotland.
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energy mix that would reduce the countrys total dependence on fossil fuels7.
Considering the fact that wind farms up to depths of 45 m are still in their prototype or
planning stage and have not been sufficiently tested, the Committee recommended
that the Government should opt for well proven shallow water technology (< 30 m)
which offers lower technical risks and associated costs. The Committee recognisedthe various conflicting interests of stakeholders with regards to Is-Sikka l-Bajda
expressed in the MRA report (Malta Resources Authority, 2005). In the Committees
opinion, some concerns expressed by the stakeholders are extremely conservative
whilst for others mitigation is required. The positive experiences and scientific
knowledge presented on offshore wind farms suggest that the mitigation is possible.
Therefore the Committee recommended that the Government of Malta should
reconsider Is-Sikka l-Bajda site for the development of an offshore wind farm.
7Deidun A., Debono G., Farrugia R.N., Mallia E., and Sant T., An Offshore Wind Farm at Is-Sikka l-Bajda AnEvaluation of Concerns from Government Stakeholders, Report submitted to the Minister for Resources andRural Affairs, July 2008.
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1.4 Project Proponent
The Ministry for Resources and Rural Affairs is the central governing body seeking to provide
a comprehensive service to the community with the following responsibilities which are
essential for the quality of life:
management of resources, including energy and water,
rural development and environmental management,
design and implementation of infrastructure works and projects,
integrated coordinationof agricultural and fisheries production
research and innovation
Protection of our environment and natural resources through sustainable exploitation for socio-
economic development is a top priority for the Ministry with the aim of improving living
standards and ensuring that a clean environment is sustained now and in the future.
Implementing a climate change policy, developing alternative sources of energy as well as
fostering a conservation culture, are all cornerstones of the Ministrys vision.
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CHAPTER 2. OBJECTIVES OF THE PROPOSED DEVELOPMENT
Malta is practically totally dependent upon imported fossil fuels for its energy needs. Malta
has no refineries. The country does no have any oil or natural gas resources. Malta is
currently a small isolated network with no interconnection or transit of electricity to mainland
Europe or any other system.
Maltas renewable energy options are limited to onshore and offshore wind energy, solar
photovoltaic and solar thermal energy, and energy from waste. Diversification of supply is the
only way to maintain energy security. The best solution towards a balanced and sustainable
energy mix should come from as many renewable energy sources as possible. Wind energy
is an essential element of a renewable energy mix that could be exploited to meet the
countrys renewable energy targets and reduce dependence on fossil fuels.
The economic advantages of onshore and offshore wind power generation technologies in the
Maltese Islands have been highlighted in studies for the Malta Resources Authority (Mott
MacDonald, 2005) and in other related documentation (MRA, 2005). Large-scale onshore
wind development has been identified as being the most cost-effective technology that can be
exploited locally. Unfortunately the potential for onshore wind farms in Malta is limited due to
lack of space and a relatively high population density. Technical constraints such as access
problems and interference with airport operations also pose a limitation on the amount of
onshore wind capacity that may be installed. Offshore wind in shallow waters, though more
expensive and posing a greater technical and logistic challenge, is the second best
technology option open to Malta in terms of costs (Mott MacDonald, 2005).
The principle driving forces behind the proposed Sikka l-Bajda offshore wind farm having a
maximum capacity of 95 MW are to:
reduce Maltas dependency on oil for electricity production.
generate clean renewable electricity, reducing emissions of greenhouse gases
and other pollutants.
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2.1 Benefits of the Development
The main benefits of an offshore wind farm at Sikka l-Bajda are:
(i) A substantial increase in the contribution of renewable energy contributing to a
reduction in national greenhouse gas emissions
(ii) A contribution towards attainment of Maltas national renewable energy targets
(iii) A contribution towards an enhanced and diversified energy mix, reducing Maltas
dependency on imported fossil fuels and thus increasing the security of energy
supply in the country.
Additional benefits of the proposed wind farm include:
(i) Providing the clean and green image of the country
(ii) A new major tourist attraction
(iii) Safeguarding the local marine environment by possibly designating a zone at
the wind farm as a marine conservation area
There can also be economic advantages associated with increased RES deployment such as
industry growth and job creation possibly in new sectors if Malta is capable of exploiting such
opportunities.
2.2 Proposed Timing
The following chart shows the indicative timeframes of the proposed development. Theproject will be accomplished by a private developer after a selection process. The
Government of Malta will provide the marine site and Enemalta as the distribution system
operator has to provide the developer with network connection terms. The developer will
require an authorisation and a licence from the Malta Resources Authority. The lifetime of the
wind farm is 20 years, although it may be technically feasible to increase it to 25 years.
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Figu
re2.1ProjectTimeframes
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CHAPTER3. PHYSICAL CHARACTERISTICS OF THE SITE
3.1 Site Selection Criteria for Offshore Wind Farm
The main technical site selection criteria for an offshore wind farm include:
- wind conditions at site. These are characterised by the annual mean wind speed at a
given height above sea level and should be high enough to justify the investment in
the project.
- sea depth. Existing well proven technology is limited for shallow waters not deeper
than 25 m.
- distance from the coast. Constructing the wind farm further away from the coast will
reduce any impacts onshore, such as visual and noise impacts and the impacts of
shadow flicker. Wind turbines need to be sited at a suitable distance from residential
settlements to mitigate these affects. Turbines designed for offshore farms are much
larger in size than those normally installed on land in areas close to residential
settlements. Offshore turbines have a capacity in the range of 2 to 5 MW and have
diameters between 80 and 126 m. Their tip height ranges from 120 to 164 m above
sea level. Larger setback distances from settlements are therefore required for
offshore wind farms. The noise level generated at the individual turbine locations will
be around 95-102 dB(A), depending on type and wind speed conditions. A typical
wind farm on land consisting of ten wind turbines, all at a distance of 350 m would
create a noise level of 35-45 dB(A) under the same wind conditions (Sustainable
Development Commission, 2005). A longer distance is expected in the case of
offshore wind farms as the attenuation of noise at sea is slower than on land.
Shadow flicker, which is the stroboscopic effect of the shadows cast by rotating
blades of the turbines in the presence of the sun, is one important constraint that
limits the installation of turbines closer to residential settlements. The distancerequired to mitigate shadow flicker effects depends on the geographic location of the
settlements with respect to the wind turbines.
Whilst the distance of the wind farm should be increased as much as possible from
the shore to minimise any impacts on land, the distance should not be too large to
raise the electrical infrastructural costs to connect the wind farm to the grid and
electrical energy dissipation losses.
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In addition, there are a number of planning and environmental factors that need to be
considered when selecting a site. Special considerations are taken in account to avoid or
mitigate any possible impacts on the natural environment and other activities through an
Environmental Impact Assessment. These are addressed in sections 5, 6 and 7.
3.2 Site Location and Description
Sikka l- Bajda is located approximately 1.5 km from Il-Ponta ta' l-Arax (Melliea) to the north
of Malta and located within Bunkering Area 1, see Figure 3.1.
3.3 Physical Characteristics
Sikka l-Bajda is a reef covering an area of approximately 2.2 km x 0.5 km composed of an
outcrop of globigerina. According to Admiralty Chart (Figure 3.1) the reefs depth varies
between 10.4 m to less than 20 m. There are in addition further outcrops in the general area
within waters shallower than 25 m.
3.4 Environmental Aspects
Is-Sikka l-Bajda is a candidate Marine Protected Area as identified by the Structure Plan.
According to the G.A.S. (2003) survey, the reef and the surrounding area is mainly
characterized by Posidonia oceanicasettled on matte, with a high bed density and with small,
isolated patches of sand and coarse sediment (refer to Figure 3.3). Posidonia oceanica,
considered as a marine keystone species, is a seagrass which is endemic to the
Mediterranean Sea, listed as a priority habitat within Annex I of the Habitats Directive,
Schedule I of LN 311 of 2006.
Rdum tal-Madonna, which is 1.5 km away from the reef is a Special Protected Area (SPA, by
virtue of the Birds Directive) and a Special Area of Conservation (SAC, by virtue of the
Habitats Directive). Rdum tal-Madonna is designated as an SPA principally for its
internationally important colony of Yelkouan Shearwaters. Cory Shearwaters also breed
there. The area around the cliff is a rafting zone for these sea birds.
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Figure 3.1: Bathymetric map - Sikka l-Bajda
Extract from Admiralty Chart 2537- Edition No. 2; Edition Date 6 March 2003Depth in metresScale 1: 50,000
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Figure 3.2: Views of Sikka l-Bajda
Panoramic view of Sikka l-Bajda - Viewpoint : Rdum tal-Madonna
Panoramic view of Sikka l-Bajda - Viewpoint : Rdum l-Ahmar
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Figure 3.3 - Extent of Posidonia oceanica meadows in local coastal waters non-yellow and non-orange areas denote Posidonia oceanica settled on sand, matte orbedrock (Source: G.A.S., 2003).
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3.5 Site Usage
In an assessment carried out by the Malta Resources Authority in 2005, a consultation
exercise with key stakeholders8 was carried out to identify main impacts and uses of a
number of shallow water sites including Sikka l-Bajda (MRA, 2005).
3.5.1 Fishing
Sikka l-Bajda was noted by the Fisheries Conservation and Control Division as an
important fish breeding area and popular fishing ground. In addition, fish farms are
currently located approximately 500 metres at the closest point of the existing
designated bunkering site and around 1.7 km from Sikka l-Bajda.
3.5.2 Bunkering
According to the Malta Maritime Authority, Sikka il-Bajda is used for bunkering
purposes in certain adverse weather conditions. It was noted that in 2004 around
13.5% of bunkering activity (ship to ship by bunker barge) was carried out at the site.
3.5.3 Sports, leisure and coastal recreation
The Malta Tourism Authority indicated that the site is a potential diving site and as
asset for the diving industry.
According to Wood and Wood (1999), Sikka l-Bajda is a highly recommended diving
site (4 stars). It is accessed by boat only and is an exposed offshore reef where
surge and surface chop are to be expected along with light currents. It is rarely dived.
Its average depth is 15 m and maximum depth at 25 m though it is over 70 m beyond
the drop off point. It has an average visibility of 30 m.
The Malta Sailing Federation and the Royal Malta Yacht Club through the KunsillMalti ghall-Isport noted that Sikka l-Bajda is on course for the return journey of the
Rolex Middle Sea Race and on the course of the Gattopardo Race (both ways). In
addition it was further noted that the site is also on course of other sailing races
(Triple handed Round Malta, Single handed Round Malta, Fully Crewed Figure of
Eight, Double handed figure of Eight).
8 Consultation was carried out with the following stakeholders: Malta Maritime Authority (MMA); Malta
Environment and Planning Authority (MEPA); Malta Tourism Authority (MTA); Fisheries Conservation andControl Division (FCCD); Enemalta Corporation (EMC); Malta Communications Authority (MCA); Departmentof Civil Aviation (DCA); Malta International Airport (MIA); Malta Air Traffic Services Ltd. (MTS); OilExploration Department (OED); Armed Forces of Malta (AFM); Malta Enterprise (ME); Kunsill Malti Gall-Isport (KMS).
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3.6 Wind Resources at Site
Maltas wind energy resources have been studied for a number of years by the Institute for
Energy Technology of the University of Malta9. It has, for a number of years, been carrying
out studies to qualitatively and quantitatively characterise wind conditions at different onshore
locations in Malta and Gozo. The studies have been based on wind speed measurements at
specific onshore sites combined with model calculations (e.g. WASP10
). Results from studies
have been published nationally and internationally. The Meteorological Office11
, as well as
the Physical Oceanography Unit12
and the Atmospheric Pollution Monitoring Unit13
of the
University of Malta, and various other entities are also monitoring wind parameters for various
and diverse projects or end uses.
Farrugia, et al.(2000) investigated the potential of various offshore sites by extrapolating the
long term wind speed at Luqa airport using WASP. The annual wind speed at Is-Sikka l-
Bajda at 45 m above sea level was estimated to be in the range of 7.0 8.0 m/s. Through a
separate wind mapping exercise, Mott MacDonald (Mott MacDonald, 2005) has estimated
that the offshore wind speed at this site is 5.7 m/s at 10 m height.
Other studies in the Mediterranean
A wind resource map for the entire Mediterranean has been produced in an ALTENER project(ALTENER 2002-065)
14, which shows that the mean wind speed for the Maltese waters is in
the range 6.5 - 7.5m/s at 60 m above sea level, see Figure 3.4 below.
9 Institute for Energy Technology, University of Malta. Website: http://www.home.um.edu.mt/ietmalta
10 Wind Atlas Analysis and Application Program, www.wasp.dk
11 The Meteorological Office, Malta International Airport, Luqa, Malta. Website: http://www.maltairport.com
12 Physical Oceanography Unit, IOI - Malta Operational Centre, University of Malta, Msida, Malta.13
Atmospheric Pollution Monitoring Unit, Department of Physics, Faculty of Science, University of Malta, Msida.14
www.owemes.org
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Figure 3.4 Wind Map for the Mediterranean
(source: www.owemes.org; Accessed July 2008)
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CHAPTER 4. DESCRIPTION OF THE PROJECT
4.1 Detailed Components of the Proposed Development
The principal components of the Sikka l-Bajda Wind Farm will include:
up to 19 five-megawatt wind turbines15
power cables between the turbines and from the wind farm to the shore
an optional offshore substation
a meteorological mast (onshore oroffshore)
scour protection (where appropriate)
onshore cabling and associated works
an onshore substation
Figure 4.1 below shows the area that is being proposed for the wind farm development.
Figure 4.1 Area for proposed development
15The 5 megawatt turbines are the largest turbines currently available on the market. In case smaller machines areused, their number will have to be increased to reach the required capacity of up to around 95 megawatts (such asup to twenty six 3.6 megawatts turbines or up to thirty 3 megawatt turbines)
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Table 4.1 shows the co-ordinates of the area corners indicated in Figure 4.1. The site
indicated has an area of around 11 km2and covers the Sikka l-Bajda reef and the surrounding
shallow waters outcrops up to a depth of 25 m.
Table 4.1 Sikka l-Bajda Offshore Wind Farm Area
Area Corner Latitude Longitude
1 N 35058 48 E 14
025 18
2 N 36000 48 E 14
021 54
3 N 36001 12 E 14
022 11
4 N 36001 00 E 14
023 48
5 N 35059 30 E 14
026 12
The proposed Sikka l-Bajda wind farm would be located 3 to 5 km from the tourist
accommodation area of St. Pauls Bay, Bugibba and Qawra and 5 km away from Ghadira
beach. The closest residential settlement at Qawra (Ta Far Ben area) is about 3 km from the
site.
Presently, the national grid is an isolated one and is too small to bear a wind farm capacity of
95 MW due to network stability issues. Enemalta intends to install an interconnecting cable
with Sicily which will link the local grid to that in mainland Europe. This interconnection will
permit the safe integration of the proposed wind farm in the Maltese electricity supply
network.
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4.2 Wind Farm Design
At this stage it is difficult to determine the generating capacity of the individual turbines that
will be installed at Sikka l-Bajda and their exact positioning. It will depend on the commercial
availability of the turbines at the time of construction as well as on the outcome of detailed
technical studies of the site (wind resource, sea conditions and geotechnical). The largest
wind turbines currently available on the market, with a capacity of 5 MW are being considered
for this proposal.
The following wind farm scenario is being considered as a basis for the EIA process:
Wind Farm Capacity 95 MW
Turbine Rating 5 MW
Number of Turbines 19
Turbines
The hub height for the 5MW turbines will be up to 100 m above mean sea level, with the
maximum tip height of 163 m. The distance between the blade tip and the sea level will be
around 37 m.
The wind turbines that will be installed at Sikka l-Bajda will be technologically advanced and
quiet. They will consist of three rotor blades assembled to a nacelle which houses the
gearbox, generator and other ancillary equipment (refer to Figures. 4.2 and 4.3). The
nacelles will be mounted on top of tubular steel towers, each having a maximum diameter of 5
to 6 m at the base (tower, foundation interface). Offshore wind turbines use the same
technology as onshore turbines however their design is more robust to withstand the harsh
weather conditions at sea. The turbines have minimum maintenance requirements and
include the following features:
Long term corrosion protection
All external turbine components are painted with offshore-grade corrosion protection
systems that effectively minimize any corrosion caused by the salty water and air. The
nacelle and tower are normally fully enclosed and climate control equipment is
embedded to maintain the internal humidity levels below the corrosion threshold.
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Safety and accessibility features for service engineers and technicians
The lightning protection system minimizes the risk of damage from lightning strikes that
occur frequently in some locations offshore. The turbines are normally fitted with
navigational lights and aerial warning lights meeting the relevant safety standards.
Health and Safety equipment for the crew is provided at foundation level. The colour of
the towers used for the turbines at Sikka l-Bajda will be selected after consultation and
agreement with the regulatory authorities, but it is likely that the upper sections will be a
low visibility grey and the lower sections yellow to aid visibility to navigation.
Equipped with sophisticated monitoring and control systems (SCADA)
The turbines are equipped with variable speed and blade pitch systems that work
together to maximize energy yield while mitigate high loads on the turbine components.
Figure 4.2 Main Components of a Wind Turbine
(Source: www.vestas.com; Accessed July 2008)
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Figure 4.3 Offshore Wind Turbine Schematic. Monopile type foundation shown.
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Wind Farm Layout
The wind turbines will be spaced and positioned in a way to minimize turbine-to-turbine
interference in the wind flow. The exact spacing required depends on the size of the turbineselected, with increased spacing used for the larger turbines. In an offshore wind farm, as a
rule of thumb, interspacing between individual turbines is around 8 times the rotor diameter in
the prevailing wind direction and 5 times the rotor diameter cross wind. This spacing has
shown to lead to an acceptable balance between yield maximisation and making efficient use
of the limited space available. The interspacing can vary somewhat due to local
circumstances (i.e. seabed conditions or water depth). The minimum distance between the
turbines will be circa 400 m while the maximum will be circa 1000 m. Figure 4.4 shows the
positions of the wind turbines in the allocated site. The positions are only indicative. The final
wind turbine positions can only be determined after detailed wind flow and geotechnical
studies have been performed.
Figure 4.4 Offshore Wind Turbine Layout (19 X 5 MW turbines). Turbine locations
are only indicative and are subject to change
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Foundations
The purpose of the foundation (see Figure 4.3) is to provide support for the wind turbine
structure that is installed above sea level. The foundation has to withstand the hydrodynamicforces of the sea, the weight of the entire turbine system above it and the loads experienced
by the turbine during operation. The foundation includes a steel platform and a ladder (see
Figure 4.3) that will provide access to the turbine and a safe working environment for the
installation and maintenance crew. The foundation also provides an access point for the
power cables, usually through a tube assembled to the structure. In steel structures,
corrosion protection is provided using sacrificial anodes, similar to those found on oil rigs.
The final selection and design of the foundation, upon which the turbines will be installed, will
depend on the local sea depth, geophysical characteristics of the sea-bed, sea conditions and
the turbine selected. Four possible foundation types may be considered:
a. Gravity type Foundation
This design consists of a concrete caisson that will be fabricated on land. It will then
floated and towed to the site where it will be then submerged and filled with gravel, sand
or concrete to obtain the required weight. The total foundation footprint is around 1000
m2.
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Figure 4.5 Gravity-type foundation
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b. Monopile Foundation
This is a free-standing steel pipe, typically 3.5 6 metres in diameter which is rammed to
about 20 metres into the sea-bed (see Figure 4.6). Since the foundation at Sikka l-Bajdais very likely to be composed of solid rock over the entire area, a guide hole will have to
be drilled before inserting the pile. The total foundation footprint is around 25 m2.
Figure 4.6 Monopile foundation
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c. Tripod Foundation
This design consists of a central steel tube supported by three legs (Figure 4.7). The
three support points will be piled into the sea bed by means of thin steel tubes about onemetre diameter. The total foundation footprint is around 170 m
2.
Figure 4.7 Tripod foundation
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d. Jacket foundation
This design is a four-legged lattice structure constructed from steel tubes. The jacket
structure is embedded in the sea floor using steel tubes, as with the tripod foundationstructure. The total foundation footprint is around 290 m
2.
Figure 4.8 Jacket Structure
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Connection Cables and Offshore Substation
A network of undersea cables is required to interconnect the individual turbines and to
transmit the bulk power to the onshore substation. The cables will have a diameter between10 to 25 cm. They will consist of 3-core copper or aluminium conductors with suitable
electrical insulation and steel armouring to prevent damage from external sources (e.g.
anchoring). The cables will include also communication links as part of the SCADA system
network used to monitor and control the individual turbine operation from a control room
onshore. Figure 4.9 shows a photo of the cross-section of a typical cable to be used.
Two options may be considered for connecting the wind farm to the onshore substation:
Option 1: The turbine interconnecting cables, rated at 33kV, will be bunched to up to four
strings of cables which will extend the land-based substation (see Figure 4.10(a)).
Option 2: The turbine interconnecting cables, rated at 33kV, will be connected to a single
offshore substation platform, from where a single 132kV cable will transmit the electricity to
land (see Figure 4.10(b)). The offshore substation will be mounted on a platform around 20 m
by 20 m in size. The substructure supporting this platform will be similar to those shown in
Figures 4.5 4.8. A photo of a typical offshore substation is presented in Figure 4.11.
These connection options will still have to be confirmed by further studies during the detailed
design of the wind farm which will be carried out at a later stage. Option 2 is preferred for
Figure 4.9 Offshore wind farm 3-core cable
(source:www.abb.com, Accessed: August 2008)
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Figure 4.10(a) Typical Wind Farm Cabling (Option 1)
Figure 4.10(b) Typical Wind Farm Cabling (Option 2)
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two reasons: 1. the electrical connection equipment to be housed in the land-based
substation requires a smaller footprint and 2. a single 132 kV cable minimises the number of
crossings with existing submarine cables, such as for example the GO p.l.c. and Melita
communication cables.
The wind farm cables at sea will be laid down on the sea bed. A no-anchor zone (normally
200 m wide) would be required. Otherwise they will be buried to a nominal depth of circa 0.5
1.0 m below the sea-bed surface where possible. In this case the actual burial depth will be
subject to the outcome of the geophysical studies and the final detailed design. For burying
the cables, a trenching tool will have to be used. It is estimated that between 25 and 50 km of
cabling will be needed for the entire project.
It is the plan to land the offshore wind farm cables at a convenient offshore point. The windfarm cables will then extend to the onshore substation that will have to be constructed to be
able to connect the wind farm to the Enemalta national grid. The exact size and location of
this substation will be determined later on. Trenching will be required to bury the cables from
the sea shore to this onshore facility, as shown in Figure 4.12. The trenching path will have to
be modified depending on the location of the substation. However existing pathways will be
used as far as possible to minimise any impacts on the natural terrain features.
Figure 4.11 An offshore substation(source:www.bowind.co.uk, Accessed: August 2008)
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Figure 4.12 Typical onshore cabling connecting wind farm to the new substationthat will be constructed to connect the wind farm to the Enemalta electricity grid. Thesize and exact location of this substation will be determined later on.
Scour Protection
Installing structures on the seabed will alter the local flow characteristics which can in turn
results into localized erosion or scouring. Scour protection will therefore be installed where
necessary around the wind turbine foundations and cables at sea to offset these effects. The
scour protection will consist of rock boulders, grout-filled bags or concrete mattresses.
Onshore Facilities
The wind farm onshore facilities will be located at the new substation, The onshore facilities
will include the electrical equipment to connect the wind farm cables to the national Enemalta
grid. All work involved in the grid connection will be carried out in close co-operation with
Enemalta
A control room will house the SCADA (Supervisory Control and Data Acquisition) which will
be used to monitor and control remotely the operation of the wind farm. The operation room
may be located within a distant building as it will be connected to the wind farm through a
data communications (internet) network through fibre-optic cables and switches.
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Estimates for Electricity Production from Offshore Wind Farm
With the limited information available about local wind conditions, it is not possible to predict
the energy yield from the wind farm at Sikka l-Bajda with sufficient levels of accuracy. Beforesuch development is initiated, it will be vital to take site specific wind measurements for high
altitudes (at least 60 m above sea level).
Table 4.2 below shows the predicted electricity generated from the wind farm. For these
calculations, a mean wind speed of 5.7 m/s at 10 m height with an uncertainty of 10% was
assumed. A Weibull statistical distribution was used, taking the k parameter equal to 1.84.
The wind shear exponent used to correct for the increase in wind speeds at higher altitudes
was set at 0.11. It should be emphasised that such results are only indicative and further
detailed studies of the wind resource are required, including the site measurements which are
essential to be able to quantify the wind farm yield with a lower uncertainty.
Table 4.2 Indicative estimates for energy yield
(19 X 5 MWTurbines)
Wind Speed at 10m asl (10%) m/s 5.70.57
Turbine hub height m 100
Wind speed at hub height m/s 7.34
Turbine energy yield/annum GWh/annum 14.1
Turbine capacity factor % 32
Wind farm array loss % 12
Turbine reliability % 95
Electrical losses % 2
Net wind farm energy yield GWh/annum 21940
Equivalent full load hours Hours 2303425
Wind farm capacity factor % 265
It is estimated that the wind farm will supply the north of Malta and Gozo with a minimum of
180 Gigawatt-hours of clean electricity annually. This is equivalent to at least 7.5% of the
present (2008) global electricity consumption in Malta and 5.5% of the forecasted
consumption for 2020. The latter percentiles have been computed on the projected electricity
consumption figures presented in table 4.3.
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Table 4.3: Predicted electricity demand in Malta for 2008-2020
Year Annual
Electricity
Demand in
GWh/annum
2008 2,389
2009 2,507
2010 2,625
2011 2,693
2012 2,781
2013 2,859
2014 2,937
2015 3,015
2016 3,093
2017 3,133
2018 3,173
2019 3,213
2020 3,253
Source: Lahmeyer International, 2008, Report Energy Interconnection Malta Europe
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Estimates of saved emissions that would otherwise be emitted by an oil-fired power station
The following table lists the carbon emissions and other pollutants that would be offset
through the offshore wind farm project. The calculations are based on a nominal yield of 219Gigawatt-hours of clean energy per annum from the wind farm. It is assumed that the fossil-
fuel power station consumes heavy fuel oil (0.7% sulphur content) at a rate of 0.3 kg/KW-Hr
and an efficiency of 31.5%.
Table 4.4: Estimated annual emission savings through Offshore Wind Farm Project16
Carbon Dioxide17
185,000 tonnes
Sulphur Dioxide 858 tonnes
Nitrogen Oxides 500 tonnes
Total suspended particulate matter (TSP)125 tonnes
Carbon Monoxide 38 tonnes
Polychlorinated Dibenzodioxin (PCDD) andPolychlorinated Dibenzofuran (PCDF)emissions
6.3 milligrams (total toxic equivalent)
Estimates for savings on Heavy Fuel Oil imports
It is estimated that the Offshore Wind Farm Project will save circa 390,000 of barrels of heavy
fuel oil imports every year. This estimate is based on a nominal yield of 219 Gigawatt-hours
of electricity from the wind farm and a power station fuel consumption of 0.3 kg/KW-Hr.
16finalised estimates will be carried out after necessary detailed technical studies are performed
17computed assuming a CO2 emission factor of 0.85 tonnes/MWh, National Allocation Plan for Malta 2008 - 2012
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4.3 Pre-Construction Engineering and Environmental Studies
The project developer will undertake the following engineering and environmental studies,
which involve a limited (minor) intervention to the site before the actual construction of the
wind farm. The studies will enable the collection of site specific information that is essential
for assessing the project feasibility, for designing the turbine installations and to determine the
optimized wind farm layout.
a. Wind Measurements
Any of the following four options is likely to be adopted by the project developer to
measure the local wind resource:
i. Option 1 Installation of an offshore meteorological station on the Sikka l-Bajda
reef.
The station will consist of a truss tower installed at the offshore location indicated
in Figure 4.13. It will be up to 80 m high above sea level and will be equipped
with a number of measuring devices to monitor wind conditions. Anemometers
will be installed at different heights along the mast to be able to measure the
influences of vertical wind shear (see Figure 4.15 for photograph). The tower willbe supported on a monopile foundation (similar to that shown in Figure 4.6). The
foundation monopile will have a diameter of around 1.8 m and will penetrate up to
7 m into the sea bed. This may also be equipped with instruments to collect sea
wave and current data.
ii. Option 2 - Installation of an onshore meteorological station at Ahrax Point.
The station will consist of a mast equipped with wind monitoring devices as for
option 1above. The mast will be up to 80 m above ground level. The mast will
be located as shown in Figures 4.13 and 4.14. It will be supported vertically by a
small concrete foundation and a number of guy wires (see Figure 4.16).
iii. Option 3 Installation of a remote sensing wind measuring system and a 60 m
high meteorological mast at Ahrax point
The station will consist of LiDAR or SODAR ground-based wind remote
measuring equipment (see Figures 4.17 and 4.18) and a wind mast. The remote
measuring equipment is a newcomer to the wind industry and is being used in
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addition to wind anemometer masts to capture wind speeds at higher altitudes
and across larger areas. Despite the considerable advancements in such
techniques, remote sensing systems still suffer from considerable drawbacks. To
ascertain the reliability of the collected data using remote sensing, a windmonitoring mast, with a typical height of 60 m would still be installed.
iv. Option 4 - same as Option 3, however the remote sensing system is installed on
a jack-up vessel at the offshore site.
On site measurements using options 1 or 4 will provide the most reliable meteorological
data for wind resource assessment at Sikka l-Bajda but would be more expensive than
options 2 and 3. The measurement campaigns will be taken for a temporary period (at
least one year), after which the installation masts will be removed.
Figure 4.13 Proposed locations for installation of temporary windmonitoring stations. Locations subject to change.
Offshore Meteorological
Station (Options 1 & 4)
Onshore Meteorological
Station (Options 2 & 3)
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Figure 4.14 Proposed locations for installation of temporary windmonitoring stations on land (options 2 and 3). Locations subject to change
Figure 4.15 Offshore Meteorological Station
(Source: www.ewec2006.info, Accessed August 2008)
Onshore Meteorological
Station (Options 2 & 3)
Existing camping site
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Figure 4.16 Onshore Meteorological Mast
Figure 4.17 Wind LiDAR equipment
(Source: WindTech International, July/August 2007)
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Figure 4.18 Two models of SODAR equipment
(Source:
www.biral.com, Accessed August 2008)
b. Environmental, Geophysical and Geotechnical Surveys
A specially equipped offshore survey vessel will be required to perform environmental,
geophysical and geotechnical studies of the Sikka l-Bajda site.
Figure 4.19 A typical survey vessel
(source: www.fugro.com; Accessed August 2008)
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Environmental Survey
Detailed seabed environmental surveys are necessary to assess the potential impacts of
the proposed works on the marine life, both at the site of the wind-farm as well as alongthe submarine cable route.
The environmental survey allows for acquisition of detailed information on the physical,
chemical, biochemical and biological characteristics of the seafloor sediments and water
samples. A typical survey would involve:
a) GPS positioning for precise location of sampling points;
b) Grab usage for sediment sampling and analysis of macrobenthos;
c) Box corer for sampling and analysis of chemical, physical and biochemical
analysis;
d) Niskin bottle for water sampling to determine presence of heavy metals,
hydrocarbons, nutrients, bacterial load and chlorophyll concentration;
e) CTD measurement along the water column in order to obtain composite depth
profiles of the principal physical parameters such as salinity, temperature,
dissolved oxygen and pH;
f) Trawler net for fish sampling in accordance with scientific standards.
Figure 4.20 Typical box corer(Source:www.whoi.edu; Accessed August 2008)
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Figure 4.21 Typical grab samplers
(Source: left: www.rickly.com; right: www.encora.euAccessed August 2008)
Geophysical Survey
The geophysical studies are intended to:
1. provide an accurate hydrological chart of the potential development areas
2. provide information on shallow geology, mapping variations in thickness of losses
or mobile sediment cover, assessment of sand waves and dunes
3. map seabed features within the potential development areas including natural
artefacts, obstructions and ship wrecks
4. identify and locate any existing boulders, inclinations, faults, cables, unexploded
ordinance or other features that may impede foundation or cable installations.
A normal survey would include the acquisition of the following:
a) GPS positioning for precise location of sampling points and profiles;
b) Underwater acoustic positioning (USBL);
c) Multibeam system for bathymetry;
d) Side Scan Sonar for seabed morphology;
e) Sub Bottom Profiler for analysis of the stratigraphy (e.g. using a boomer);
f) Magnetometer for detection of any metal cables, pipelines & wrecks;
g) High resolution seismic single trace Sparker or Minigun System for
differentiation of rock outcrops and sediments in the seabed;
h) Multichannel digital seismic acquisition system with streamer cable for high
definition of stratigraphy and lithology of seabed sediments;
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Figure 4.22 Typical Multibeam Bathymetry(Source: www.meridata.fi; Accessed August 2008)
Figure 4.23 Typical Boomer for sea bottom profiling(Source: http://www.marinegeosolutions.com; Accessed August 2008)
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Figure 4.24 Side-scan sonar tow fish and a typical image(Source: www.edgetech.com; Accessed August 2008)
Geotechnical Studies
Geotechnical studies will be required to characterise the properties of the underlying
geological strata of the sea bed for the design of the wind turbine foundations and to
assess requirements for cable laying. Sample coringusing conventional barrel rock
coring will be used for recovery of seabed cores for geotechnical analysis. The
coring will take place at each individual turbine location with diameters between 70
150 mm and up to depths of around 30 m.
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Figure 4.25 Typical geotechnical vessel equipped with core drilling equipment
(Source:www-odp.tamu.edu; Accessed August 2008)
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4.4 Component Delivery and Wind Farm Construction
Component Delivery
The wind farm components including the blades, nacelles, tower sections, electric cabling,
offshore substation parts and onshore equipment will be shipped to Malta from their country
of origin by sea. The Grand Harbour quayside facilities will be used to store and assemble
the wind turbine components during the wind farm construction phase. Additional space can
be provided by berthing a barge by the selected quayside. Special fixtures and cranes will be
used to handle the blades to prevent damage and to store them safely onshore (as shown in
Figure 4.26).
Malta has long standing experience in ship building and in the construction of offshore
structures. It could be possible that the wind turbine foundation structures are manufactured
locally. These will have to be manufactured at the Grand Harbour area where they can be
easily lifted on board the sea-vessel and transported to Sikka l-Bajda. Figure 4.27 shows a
photograph of gravity-based foundations for five-Megawatt turbines being manufactured at a
quayside in Belgium.
Figure 4.26 - Utilisation of a harbour facilities for storing and assembling
wind turbine components. (Source: www.a2sea.dk; Accessed August 2008)
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Figure 4.27 Construction of wind turbine foundations
(Source: www.flickr.com/photos; Accessed August 2008)
Wind Farm Construction
a. Foundations
The first step of the wind farm construction is the installation of the wind turbine
foundations. This installation procedure will vary depending on the foundation type used,
as follows:
Gravity type foundation (Fig. 4.5): The sea bed area on which the gravity foundation will
rest is excavated to produce a flat solid base. The foundations are floated at sea and
tugged to the wind farm site. They are then sunk to their final position by filling them with
sand, gravel or concrete. The sinking process is gradual to allow the crew to locate the
foundation in the exact location.
Monopile Foundation (Fig. 4.6): A hole is drilled into the foundation seabed using a
drilling equipment as shown in Fig. 4.31. This will allow the installation of the monopile.A steel sleeve is first driven into the seabed surface to guide the drill bit and prevent the
drilled waste material from spreading over the seabed and into the surrounding waters.
The sleeve normally extends around 1 m above the seabed. The water and waste
sediment contained in the sleeve is pumped out on a barge which filters the water,
removing the waste sediment for safe disposal. Once the drilled hole reaches the
required depth, the monopile is driven into the seabed using a specially equipped vessel
(Figure 4.28). Grout is then used to seal the gap between the monopile and the drilled
hole (Figure 4.30).
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Tripod and Jacket foundations (Figs. 4.7 and 4.8): Three or four holes are drilled into the
sea bed using the same procedure as for the monopile. The structure is located in the
correct position by aligning the holes at the feet of the structure with those drilled into the
seabed using the sea vessel crane. The small piles are inserted locking the structure tothe seabed. Grout is applied to seal the gaps between the piles and the drilled holes.
Scour protection is finally added to all foundation to prevent any erosion of the sea bed
around the foundations.
The foundation for the offshore substation will be constructed using a similar procedure as
described above.
Figure 4.28 Pile driving of monopile foundation into the sea-bed
(source: www.npower-renewables.com; Accessed August 2008)
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Figure 4.29 Drilling equipment(Source: www.flickr.com/photos; Accessed August 2008)
Figure 4.30 Application of grout to a monopile foundation (shown in red).Grout also used for other foundation types.
(Source: www.densit.com; Accessed August 2008)
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Figure 4.31 Completed installation of monopile foundation
(Source: www.eurotrib.com; Accessed August 2008)
b. Cabling
The laying of the cables will take place after all foundations have been placed installed
but before the installation of the turbines. The cable will be coiled directly from the
quayside storage facility or barge in the Grand Harbour. The interconnecting turbine
cables will be connected by pulling their ends through a J-tube installed on the turbine
foundations. The pulling is carried out using a winch that is positioned on top of the
foundation.
Figure 4.32 Cable lying(Source: www.windpowerphotos.com; Accessed August 2008)
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c. Turbines
While the foundations are installed and foundation cabling is taking place, the wind
turbine rotors, consisting of the three blades and hub will be pre-assembled onshore atthe quay in the Grand Harbour
18. These will be then lifted onto a sea vessel, together
with the turbine towers and transported to the wind farm site (see Fig. 4.33). It is likely
that the tower will be transported in sections and then lifted in place. This would be
followed by the erection of the nacelle and rotor assembly (see Figure 4.34). In certain
situations a second sea vessel is required for erecting the wind turbines. The vessel is
normally equipped with four jack-up legs which will allow the vessel crane to be in a
stable position while handling the heavy turbine parts. It is expected that each turbine
installation will take between 2 and 3 days to complete, depending on weather conditions.
Figure 4.33 Transportation of Turbine parts to offshore site for assembly
(Source: www.flickr.com; Accessed August 2008)
d. Offshore substation
The offshore substation components, including the transformer, switchgear, electrical
wiring, monitoring equipment, etc, will be assembled on a platform at the harbour and
the entire module will transported to Is-Sikka l-Bajda using a floating barge crane
vessel. It will then be erected on the substation substructure.
18Important note - Installing as many components as possible onshore instead of offshore will reduce the
constructions costs significantly.
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Figure 4.34 Erection of Turbine Rotor(Source: www.windpowerphotos.com; Accessed August 2008)
4.5 Operation and Maintenance of the Wind Farm
During the entire wind farm construction, a 500 m no-go buffer zone for all sea craft will have
to be designated temporarily for safety reasons.
It is not yet decided whether the wind farm area at Sikka l-Bajda will be designated as anexclusion zone for marine traffic. It could be possible to allow vessels to enter the wind farm.
In such case the vessels will enter at their own risk and should maintain a minimum of 50 m
clearance from the turbine foundations. The wind farm will be marked on charts and
navigational markers. The following navigational aids will be fitted, following consultation with
the Malta Maritime Authority:
Turbine foundations may be painted yellow to improve their visibility.
The perimeter of the wind farm will be marked with yellow flashing lights and radar
reflectors.
A fog horn will be installed in the centre of the wind farm.
All turbines will have aerial navigational lights installed. Only the corner lights will be
lit continuously. The others will be lit only in an emergency.
The wind farm and subsea cables will be clearly marked on the Admiralty Charts for the zone.
A Notice to Mariners will also be issued announcing the presence of the wind farm.
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The operation of the wind farm will be monitored and controlled using the SCADA system in
the control room through the data communications network. The ability to shut down
individual turbines or the entire wind farms will rest in the hand of the operator.
The Sikka l-Bajda offshore wind farm will be designed to remain operational with minimal
maintenance and supervision during its entire lifetime (20-25 years). Each turbine will be
equipped with a computer controlled system and will shutdown automatically in case of
emergency situations. Periodic maintenance, inspection and testing procedures will be
implemented to guarantee safe operation of the wind farm and minimise turbine downtime.
The following will be included in the maintenance inspections:
Wind turbine load bearing components (blades, hub attachments, bearings, etec)
Drive system (gearbox)
Foundation
Cathodic protection and coating systems
Seabed scour protection
Electrical earthing and lighting conductors
Control and electrical power systems (over speed sensors, hydraulic circuitry)
Lighting system and emergency back up
Safety and access equipment
When possible, maintenance work will be performed when no wind is blowing. Conditioning
monitoring systems implemented in the SCADA system will inform of any technical problems
in advance so that maintenance crew can plan ahead. The wind farm will be serviced using a
small vessel (around 10 m long, Figure 4.35) from a quay in the vicinity of Marfa. Any
problems discovered during the inspections will be handled as quickly as possible.
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Figure 4.35 Sea vessel used for servicing the turbines
(Source: www.windpowerphotos.com; Accessed August 2008)
4.6 Decommissioning
One of the conditions of concession of the sea space at Sikka l-Bajda with the Government of
Malta is that provision is made to remove the wind farm and associated components at the
end of the agreement.
The decommissioning phase will return the wind farm site to the condition it was in before the
construction took place. The wind farm components and will be dissembled and shipped to
shore. They will then be exported for recycling. Removal of the wind turbines and masts will
require the same type of equipment used for construction.
Due to the potential environmental impacts that are foreseen when dismantling the offshore
foundations, consultation will take place with MEPA beforehand to ensure that minimalnegative impacts are caused. Their condition will be assessed prior to removing them for
possible environmental consequences. It is expected that marine colonies have formed
around the foundations over the years and it may warrant to leave some parts in situ.
The wind farm offshore cabling will be removed and recycled. The onshore cabling from the
shore to the substation will also be removed, however it may be left in situ if the disruption
that will be caused would be unjustified.
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4.7 Health and Safety Measures
Legislative Health and Safety requirements and best practise guidelines on offshore wind
farms will be observed at all phases of the project, including detailed development of the
site, construction, operation, maintenance and de-commissioning.
The following Health and Safety Aspects will be taken for the development of Sikka l-Bajda:
Wind Farm Design
The selected wind farm components for Sikka l-Bajda wind farm, including the wind turbines,
foundations and the electrical system will meet relevant design standards. The site will be
thoroughly assessed to collect the necessary data for the wind farm design, taking the
following into considerations:
Extreme wind and wave conditions from on site measurements and analysis of
historical data. The sites vulnerability to earthquake activity will also be evaluated.
Details of sea currents
Other weather or climatic conditions, e.g. high atmospheric temperatures
Risk of lightning
Properties of the seabed
Emergency Arrangements
An emergency response plan for handling possible emergency situations, e.g. workers
falling into the sea will be drawn up and subject to regular exercises and drills. The plan will
clearly define the responsibilities of everyone with the actions to take during different
emergency circumstances. The plan will also identify a place of safety were people in need
of medical treatment and other facilities will be taken.
Temporary Facilities
Since the Sikka l-Bajda wind farm is close to the shore, accommodation facilities on site
would not be likely required. However emergency supplies, including, sleeping bags, food
and drinking water will be provided to each turbine in case that the workers will have to stay
working overnight. These supplies are also provided in situations where the weather
conditions change such that the workers would not be able to leave the turbines and returnto shore.
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Safety Equipment
All operation and maintenance personnel must wear a flotation suit and life jacket when
visiting the wind farm. They will also wear a helmet with a chin strap when climbing up theturbine. Each turbine will be equipped with first aid kits, throwing lines, lanterns and
hypothermia blankets.
Weather Conditions
The health and safety procedures will define under which weather conditions work will have
to cease. All working personnel involved, including the operators of the vessels will be
informed about conditions in which they can operate safely, following also recommendations
from the wind turbine manufactures.
Communication
It will be ensured that all members of crew will be in contact with key personnel while at
work, e.g. by mobile phones. It will be made sure that workers from foreign countries
speaking different languages can understand instructions and information. Appropriate
systems for communicating between the wind farm and the vessel, onshore facility, police,
ambulance, civil protection department and relevant authorities will be provided.
Lifting and Handling
All necessary measures will be taken to assure that lifting and handling equipment at shore
and at the offshore site will be operated safely by competent crane operators and banks
men.
Information, Training and Supervision
When working in an offshore environment, training in offshore survival techniques is a must.
All key construction and maintenance personnel working on the Sikka l-Bajda wind farm
project will be following a course which will provide training in the techniques to ensure safe
access and transfer from the boat to the turbines and vice versa. The course will cover
personal protective equipment and dangers when working in offshore environment (such as
falling into the sea).
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Safe Access
Appropriate procedures will be implemented for:
The management of sea vessels travelling to the wind farm
Working personnel and visitors accessing the wind farm
Loading and unloading supply vessels.
4.8 Raw materials and Waste
Grout will be used to install the turbine foundations. The grout used is safe and approved for
use in the marine environment.
Drilling of the seabed for installing the foundations will create rock waste material. It is
estimated that the maximum amount of rock material will be generated with monopile
foundations and will be around 400 m3
per turbine installation. Additional waste will be
generated if the electrical power cables need to be buried rather than simply laid on the sea
bed. This waste will be properly disposed at an authorised area and is not expected to be of
concern.
Waste generated during operation and maintenance work at the wind farm will include oil,
replaced turbine parts (e.g. oil filters, seals..), and chemicals normally used for cleaning,
greasing and painting. In addition domestic-type waste will be generated by personnel
working on the turbines. Special measures will be taken so that the generated waste will be
disposed of safely as required by regulation.
4.9 Employment
The proposed Sikka l-Bajda project shall provide both direct and indirect work and business
opportunities to sections of the local community during the construction and operational
phases. It is anticipated that around 50 personnel will be required during the construction
period, (which extends approximately 8 to 14 months) and around 15 full time job
opportunities for operation and maintenance of the wind farm.
The level of manpower required to construct a wind farm could be increased by fabricating
certain wind farm components (such as the towers and foundations) locally.
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4.10 Project Costs and Economic Feasibility
The project capital investment costs required depend on the following factors: the sea depth
distribution; the geology of the seabed; the size of the wind farm and its distance from the
coast; and the selected turbines and foundation types.
The cost of the electricity generated will depend, apart from the initial capital investment
costs, on the general wind conditions at the site, operating and maintenance expenses and
the financing mechanism adopted for the project.
The wind speed conditions at site, which is normally taken as the long term annual wind
speed in metres per second at the rotor hub height, is a crucial factor affecting the cost of
generated electricity. The energy content in the wind is directly proportional to the cube of the
wind speed, implying doubling the wind speed increases the energy in the wind eight fold.
Due to the lack of availability of data, in particular accurate wind data at the site for Sikka l-
Bajda for high elevations above the sea (at least 60 m above sea level), it is presently difficult
to establish an accurate estimate for the costs of wind energy.
In a study carried out by Mott MacDonald in 2005, the average cost of power for a 27 MW
wind farm at Sikka l-Bajda was estimated at 7.75 cents/kWh. This estimate was based onan estimated wind speed of 7.11 m/s at 90 m above sea level and a total capital investment of
1590/KW. However, costs of wind farm projects have increased considerably in the past
three years, especially those offshore. This has resulted from a high demand for wind turbines
and a shortfall in supply. The costs have also been affected by the increased costs in raw
materials, in particular steel which accounts for circa 90% of the total weight of wind energy
converters.
Figure 4.36 below shows the costs of energy generated from offshore wind farms at different
annual wind speeds for projects commissioned in year 2007.
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0
2
4
6
8
10
12
14
16
18
20
5.5 6 6.5 7 7.5 8 8.5 9 9.5 10
Wind speed in metres per second
CostinEurocentsperUnit(KW-Hr)
OFFSHORE
installed costs 2300/KW
OFFSHORE
installed costs 2600/KW
Figure 4.36 Costs of wind energy for offshore wind farms commissioned in 2007
(results obtained from Wind Power Monthly magazine, April 2008)
Predicted Wind Farm Capital Cost and Cost of Generation for the Sikka l-Bajda Project
Offshore wind farm prices are expected to peak at around the year 2009-2010, after which
they are expected to decrease again (EWEA (2008) Garrad (2007), Lemming et al. (2007))
due to increase turbine deployment and reduction of bottlenecks in the supply system.
Capital Costs
The wind turbines and all other equipment and services are likely to be purchased during late
2010 and early 2011. For this period, the EWEA (EWEA, 2008) predicts that wind farms in
shallow waters will cost around 2350/KW. However, a realistic uncertainty range of 25% to
50% has to be assumed to allow for the fact that wind farm will be installed in waters deeper
than 10 m and sea bed conditions are hard and pre-drilling is consequently required for
foundation pile driving. Specialised installation sea vessels would also entail higher costs
during the project construction due to their lack of availability in the Mediterranean, unlike in
the North Sea area. It is estimated that the total cost range can vary between 2940-
3525/KW19
. Therefore, the initial capital investment cost for the 95 MW wind farm will be in
the region between 280 and 335 million.
19This estimate is only indicative, based on figures provided by the European Wind Energy Association (EWEA,
2008). This is subject to detailed technical and economic evaluation that will be carried out in due course.
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Costs of Generation
Costs of generation are being computed based on an assumed long term annual wind speed
varying between 6.6 7.6 m/s at hub height. The levelised cost of energy for this wind speedrange is estimated to vary between 17 26.5 cents/KWh
20. This estimate takes into
account the uncertainties in the capital cost presented above.
Assumptions taken in computing Levelised Costs of Generation
The economic analysis is carried out using a discount rate of 8% over the assumed
lifetime of 20 years.
Annual operating and maintenance costs are taken as 3.5% of the total initial capital
investment.
Spinning reserve costs are assumed to be 0.5 cents/KWh21
Comments
It would be possible to predict the costs of electricity from the wind farm with a lower degree
of uncertainty and with a comprehensive statistical approach once detailed wind studies have
been performed for at least one year. At the same time it should be noted that it is unlikely
that the price of electricity from the wind farm will be lower than 18cents/KWhas a result of
the competitive feed-in tariffs being offered by northern European countries which also benefit
from better wind conditions (wind farm capacity factors in the order of 37.5% or higher)
Although offshore wind energy may be presently more expensive than that from conventional
power plants, it provides a supply of clean energy at a secured price over a period of 20-25
years without being susceptible to highly volatile fuel prices. In addition, there are no risks
that extra costs will have to be incurred as a result of imposed carbon emissions trading
requirements.
20This estimate is only indicative. It is subject to detailed technical and economic evaluation that will be carried out in
due course.
21Mott MacDonald had remarked that spinning reserve costs associated with wind generation are reported to vary
between 0.3 to 0.6 cents/KWh(Mott MacDonald, 2005). The exact spinning reserve cost due to the proposed windfarm will be established once detailed technical (wind and grid integration) studies are performed.
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CHAPTER5. SITE SELECTION FOR AN OFFSHORE WIND FARM INMALTA
5.1 Status of Offshore Wind Turbine Technology
Offshore wind energy is the second best technology in terms of costs. However, while land
based wind turbines have been around long enough to enable the wind industry to fine tune
the technology in this sector, experiences with offshore wind power are more recent, with the
first prototype offshore turbines installed in the early decade. The first commercial offshore
wind farms started operating in 2001.
The offshore environment makes the construction and operation of wind farms technicallycomplicated. Maintenance and repair costs are higher than for onshore wind farms. These
factors make offshore wind energy around 50-70% more expensive than onshore projects.
However, the generation costs are still competitive compared to other renewable energy
technologies.
Tables 5.1 and 5.2 below list the offshore wind farms currently in operation and those under
construction. They are concentrated in the North Sea area which benefits from very good
wind conditions. Offshore wind farms at a commercial level exist in comparatively shallow
waters (< 25 metres) and close to the coast. For such waters, gravity-type and monopile
foundations are commonly used.
Offshore s